Skip to content

fix(encryption): cap and invalidate key-cache #64186

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
susnux wants to merge 1 commit into
base: master
Choose a base branch
from
Open

fix(encryption): cap and invalidate key-cache #64186

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
35 changes: 30 additions & 5 deletions lib/private/Encryption/Keys/Storage.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
use OC\Files\Filesystem;
use OC\Files\View;
use OC\ServerNotAvailableException;
use OCP\Cache\CappedMemoryCache;
use OCP\Encryption\Keys\IStorage;
use OCP\IConfig;
use OCP\Security\ICrypto;
Expand All @@ -26,14 +27,16 @@ class Storage implements IStorage {
private string $root_dir;
private string $encryption_base_dir;
private string $backup_base_dir;
private array $keyCache = [];
/** @var CappedMemoryCache<array{key: string, uid?: string|null}> */
private CappedMemoryCache $keyCache;

public function __construct(
private readonly View $view,
private readonly Util $util,
private readonly ICrypto $crypto,
private readonly IConfig $config,
) {
$this->keyCache = new CappedMemoryCache();
$this->encryption_base_dir = '/files_encryption';
$this->keys_base_dir = $this->encryption_base_dir . '/keys';
$this->backup_base_dir = $this->encryption_base_dir . '/backup';
Expand Down Expand Up @@ -120,6 +123,7 @@ public function setSystemUserKey($keyId, $key, $encryptionModuleId) {
public function deleteUserKey($uid, $keyId, $encryptionModuleId) {
try {
$path = $this->constructUserKeyPath($encryptionModuleId, $keyId, $uid);
$this->keyCache->remove($path);
return !$this->view->file_exists($path) || $this->view->unlink($path);
} catch (UserNotFoundException $e) {
// this exception can come from initMountPoints() from setupUserMounts()
Expand All @@ -141,6 +145,7 @@ public function deleteUserKey($uid, $keyId, $encryptionModuleId) {
#[\Override]
public function deleteFileKey($path, $keyId, $encryptionModuleId) {
$keyDir = $this->util->getFileKeyDir($encryptionModuleId, $path);
$this->keyCache->remove($keyDir . $keyId);
return !$this->view->file_exists($keyDir . $keyId) || $this->view->unlink($keyDir . $keyId);
}

Expand All @@ -150,6 +155,7 @@ public function deleteFileKey($path, $keyId, $encryptionModuleId) {
#[\Override]
public function deleteAllFileKeys($path) {
$keyDir = $this->util->getFileKeyDir('', $path);
$this->clearCachedKeysBelow($keyDir);
return !$this->view->file_exists($keyDir) || $this->view->deleteAll($keyDir);
}

Expand All @@ -159,9 +165,24 @@ public function deleteAllFileKeys($path) {
#[\Override]
public function deleteSystemUserKey($keyId, $encryptionModuleId) {
$path = $this->constructUserKeyPath($encryptionModuleId, $keyId, null);
$this->keyCache->remove($path);
return !$this->view->file_exists($path) || $this->view->unlink($path);
}

/**
* Drop all cached keys stored inside the given key directory
*
* @param string $keyDir path to a key directory, with or without trailing slash
*/
private function clearCachedKeysBelow(string $keyDir): void {
$prefix = rtrim($keyDir, '/') . '/';
foreach (array_keys($this->keyCache->getData()) as $cachedPath) {
if (str_starts_with((string)$cachedPath, $prefix)) {
$this->keyCache->remove($cachedPath);
}
}
}

/**
* construct path to users key
*
Expand Down Expand Up @@ -231,8 +252,9 @@ private function getKey($path): array {
];

if ($this->view->file_exists($path)) {
if (isset($this->keyCache[$path])) {
$key = $this->keyCache[$path];
$cachedKey = $this->keyCache->get($path);
if ($cachedKey !== null) {
$key = $cachedKey;
} else {
$data = $this->view->file_get_contents($path);

Expand Down Expand Up @@ -282,7 +304,7 @@ private function getKey($path): array {
}
}

$this->keyCache[$path] = $key;
$this->keyCache->set($path, $key);
}
}

Expand Down Expand Up @@ -313,7 +335,7 @@ private function setKey($path, $key) {
$result = $this->view->file_put_contents($path, $data);

if (is_int($result) && $result > 0) {
$this->keyCache[$path] = $key;
$this->keyCache->set($path, $key);
return true;
}

Expand All @@ -334,6 +356,8 @@ public function renameKeys($source, $target) {

if ($this->view->file_exists($sourcePath)) {
$this->keySetPreparation(dirname($targetPath));
$this->clearCachedKeysBelow($sourcePath);
$this->clearCachedKeysBelow($targetPath);
$this->view->rename($sourcePath, $targetPath);

return true;
Expand All @@ -356,6 +380,7 @@ public function copyKeys($source, $target) {

if ($this->view->file_exists($sourcePath)) {
$this->keySetPreparation(dirname($targetPath));
$this->clearCachedKeysBelow($targetPath);
$this->view->copy($sourcePath, $targetPath);
return true;
}
Expand Down
167 changes: 167 additions & 0 deletions tests/lib/Encryption/Keys/StorageTest.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
use OC\Encryption\Keys\Storage;
use OC\Encryption\Util;
use OC\Files\View;
use OCP\Cache\CappedMemoryCache;
use OCP\IConfig;
use OCP\Security\ICrypto;
use PHPUnit\Framework\MockObject\MockObject;
Expand Down Expand Up @@ -400,6 +401,172 @@ public function testDeleteFileKey(): void {
);
}

/**
* Set up the mocks needed to read file keys for arbitrary paths
*/
private function mockFileKeyEnvironment(): void {
$this->config->method('getSystemValueString')
->with('version')
->willReturn('20.0.0.2');
$this->config->method('getSystemValueBool')
->willReturn(true);
$this->util->method('getUidAndFilename')
->willReturnCallback([$this, 'getUidAndFilenameCallback']);
$this->util->method('stripPartialFileExtension')
->willReturnArgument(0);
$this->util->method('isSystemWideMountPoint')
->willReturn(false);
$this->view->method('file_exists')
->willReturn(true);
$this->view->method('is_dir')
->willReturn(true);
}

/**
* Make the view return a dummy key for every path and collect the read paths
*
* @param string[] $reads
*/
private function trackKeyReads(array &$reads, ?string $uid = null): void {
$this->view->method('file_get_contents')
->willReturnCallback(function (string $path) use (&$reads, $uid): string {
$reads[] = $path;
return json_encode(['key' => base64_encode('key'), 'uid' => $uid]);
});
}

public function testGetFileKeyIsCached(): void {
$this->mockFileKeyEnvironment();
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');

$this->assertSame(['/user1/files_encryption/keys/files/foo.txt/encModule/fileKey'], $reads);
}

public function testKeyCacheIsCapped(): void {
$this->mockFileKeyEnvironment();
$reads = [];
$this->trackKeyReads($reads);

for ($i = 0; $i < 600; $i++) {
$this->storage->getFileKey('/user1/files/foo' . $i . '.txt', 'fileKey', 'encModule');
}

/** @var CappedMemoryCache<array> $keyCache */
$keyCache = self::invokePrivate($this->storage, 'keyCache');
$this->assertCount(512, $keyCache->getData());
}

public function testDeleteFileKeyInvalidatesCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('unlink')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');
$this->assertTrue($this->storage->deleteFileKey('/user1/files/foo.txt', 'fileKey', 'encModule'));
$reads = [];

$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');

$this->assertSame(['/user1/files_encryption/keys/files/foo.txt/encModule/fileKey'], $reads);
}

public function testDeleteAllFileKeysInvalidatesCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('deleteAll')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/foo.txt', 'otherKey', 'encModule');
// a sibling sharing the name prefix must stay cached
$this->storage->getFileKey('/user1/files/foobar.txt', 'fileKey', 'encModule');
$this->assertTrue($this->storage->deleteAllFileKeys('/user1/files/foo.txt'));
$reads = [];

$this->storage->getFileKey('/user1/files/foo.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/foo.txt', 'otherKey', 'encModule');
$this->storage->getFileKey('/user1/files/foobar.txt', 'fileKey', 'encModule');

$this->assertSame([
'/user1/files_encryption/keys/files/foo.txt/encModule/fileKey',
'/user1/files_encryption/keys/files/foo.txt/encModule/otherKey',
], $reads);
}

public function testRenameKeysInvalidatesCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('rename')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getFileKey('/user1/files/source.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/target.txt', 'fileKey', 'encModule');
$this->assertTrue($this->storage->renameKeys('/user1/files/source.txt', '/user1/files/target.txt'));
$reads = [];

$this->storage->getFileKey('/user1/files/source.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/target.txt', 'fileKey', 'encModule');

$this->assertSame([
'/user1/files_encryption/keys/files/source.txt/encModule/fileKey',
'/user1/files_encryption/keys/files/target.txt/encModule/fileKey',
], $reads);
}

public function testCopyKeysInvalidatesTargetCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('copy')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getFileKey('/user1/files/source.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/target.txt', 'fileKey', 'encModule');
$this->assertTrue($this->storage->copyKeys('/user1/files/source.txt', '/user1/files/target.txt'));
$reads = [];

$this->storage->getFileKey('/user1/files/source.txt', 'fileKey', 'encModule');
$this->storage->getFileKey('/user1/files/target.txt', 'fileKey', 'encModule');

$this->assertSame([
'/user1/files_encryption/keys/files/target.txt/encModule/fileKey',
], $reads);
}

public function testDeleteUserKeyInvalidatesCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('unlink')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads, 'user1');

$this->storage->getUserKey('user1', 'publicKey', 'encModule');
$this->assertTrue($this->storage->deleteUserKey('user1', 'publicKey', 'encModule'));
$reads = [];

$this->storage->getUserKey('user1', 'publicKey', 'encModule');

$this->assertSame(['/user1/files_encryption/encModule/user1.publicKey'], $reads);
}

public function testDeleteSystemUserKeyInvalidatesCache(): void {
$this->mockFileKeyEnvironment();
$this->view->method('unlink')->willReturn(true);
$reads = [];
$this->trackKeyReads($reads);

$this->storage->getSystemUserKey('shareKey_56884', 'encModule');
$this->assertTrue($this->storage->deleteSystemUserKey('shareKey_56884', 'encModule'));
$reads = [];

$this->storage->getSystemUserKey('shareKey_56884', 'encModule');

$this->assertSame(['/files_encryption/encModule/shareKey_56884'], $reads);
}

#[\PHPUnit\Framework\Attributes\DataProvider('dataProviderCopyRename')]
public function testRenameKeys($source, $target, $systemWideMountSource, $systemWideMountTarget, $expectedSource, $expectedTarget): void {
$this->view->expects($this->any())
Expand Down
Loading